By way of general background, referring to FIG. 1, a harvester combine 10 is used to harvest crops, such as wheat. The combine has a header 11 at the front for reaping the wheat and collecting it into a feederhouse 12 where it is carried to a thresher 13 within the combine 10. The thresher 13 separates the grain and chaff from the straw then directs the partially clean grain to the shoe, where chaffer and sieves 14 further winnow the chaff from the grain. The straw and chaff are discharged out the back 19 of the combine 10 and the clean grain is collected at the bottom of a grain elevator 15. In this implementation, the elevator 15 is a paddle-type, endless-chain conveyor that lifts the grain on paddles upward to an auger 16 which in turn moves and discharges 17 the grain into a hopper 18.
Referring now to FIGS. 2 through 4, the paddle-type elevator 15 is formed by an elongated rectangular housing 21. The bottom 22 of the housing 21 is located near the lower area of the combine 10 where the clean grain is received from the chaffer and sieves 14. The top 23 of the housing 21 is located near the upper part of the combine where grain is poured into the auger 16 and thence to the hopper 18. Between the bottom 22 and top 23 of the housing 21 is an endless link chain 27 which rides within the housing 21 between a bottom sprocket 25 near the bottom 22 of the elevator 15 and a top sprocket 26 near the top 23 of the elevator 15. Between the bottom 25 and top 26 sprockets and separating the chain 27 is an intermediate wall 28 that divides the elevator housing 23 into two mostly vertical chambers. Incorporated into the links of the chain 27 are flexible paddles 29 that scoop up grain 30 from the bottom 22 of the elevator 15 and raise the grain 30 between the intermediate wall 28 and the inner wall of the housing 21 to the top 23 of the elevator 15, where the grain 30 is flung or falls down from the paddle 29 through the elevator outlet 24 to the auger 16, which discharges 17 it into the hopper 18. The flexible paddles 29 are supposed to form a seal between the intermediate wall 28 and the other inner surfaces of the elevator housing 23, but the chain 27 is not intended to tide on the intermediate wall 28.
FIGS. 3 through 4B show how the paddles 29 are incorporated into the chain 27. A paddle link 35 is incorporated into the endless chain 27. The paddle link 35 has a paddle support 36 to which a flexible paddle 33 is secured by a fastener 34. A gap 39 in the paddle 33 allows the chain 27 to pass through. Paddles 33 are constructed of layers of flexible materials, such as rubber and cord. The paddle link 35 usually forms one of the outer chain plates 31, which are linked to inner plates 32 by pins 37. Rollers 38 separate the inner plates 32 and the pins 37 hold the plates, 31 and 32, together.
Referring now to FIGS. 5 and 10, a problem with paddle-type elevators 15 is that, as the paddles 29 scoop up grain, the weight of the grain 30, as well as friction between the outer edge of the flexible paddle 33 and the inside walls of the elevator housing 23, cause the outer edge of the paddle 33 to flex backward, as shown at 41, which in turn causes the paddle link 35 to swivel back and rub against the intermediate wall 28, as shown at 42. Because the paddle link 35 swivels back under load, the force exerted by one corner of the paddle link 35 against the intermediate wall 28 is concentrated (as at 42), which results in premature wear to the intermediate wall and the paddle link 35. When the wear to the intermediate wall 28 is too great, or the wear creates gaps, holes, or tears in the intermediate wall 28, the only option is to replace the elevator, which is an expensive and time consuming repair. Because this wear tends to occur during the peak of harvesting, the expense and delay of repair can cause significant losses to the farmer, What is needed is a solution to the problem of such wear to a paddle-type elevator.